This invention relates generally to the detection of caffeine in a beverage and, more particularly, to a disposable test sheet that enables a consumer to determine the caffeine concentration of a beverage at the time of consumption and to compare the caffeine concentration to a numeric range and representative beverages within that range.
Consumers have become increasingly concerned about the effects that caffeine may have on their bodies. For example, pregnant women may avoid caffeine due to its teratogenic effect. Others may avoid caffeine because it is a known diuretic. Others simply desire to avoid caffeinated beverages during the evening hours due to its stimulating effect that may lead to insomnia.
Various devices have been proposed in the art for determining the concentration of caffeine in a beverage, such as the dipstick device disclosed in U.S. Pat. No. 5,610,072 to Scherl, et al. Although assumably effective for their intended purposes, the existing devices are not portable and do not provide for a disposable sheet that allows a consumer to determine the caffeine concentration of a beverage sample and to compare an identified numerical range to representative beverages having similar concentrations.
Therefore, it is desirable to have a caffeine testing device that enables a consumer to determine the caffeine concentration of a beverage by comparing a test result color with color gradations on an integral color chart. Further, it is desirable to have a caffeine testing device which enables a consumer to compare the caffeine concentration of a beverage with predetermined concentrations of other beverages.
A caffeine testing device according to the present invention includes a test sheet constructed of a flexible and disposable material such as cloth, paper, or cardboard. Therefore, the test sheet may be constructed in the form of a napkin, coaster, or the like. The test sheet includes a reagent section on which a consumer may place a sample of a beverage, e.g. a few drops, for testing. The reagent section is impregnated with a reagent which, when reacted with caffeine, produces a characteristic chromogenic change which corresponds to a particular caffeine concentration. This change is observable in that the chromogenic change produces a color that is characteristic of the respective caffeine concentration of the beverage sample.
The test sheet further includes a color chart having a plurality of color gradations corresponding to the possible color variations that may result from a reaction between the reagent and a beverage sample. The color gradations may be arranged as concentric sections surrounding a centrally positioned reagent section or in a more conventional tabular list format. The color chart includes numerical indicia representing the caffeine concentration associated with each respective color gradation. Therefore, a consumer is able to determine a caffeine concentration range of a beverage sample by matching the color of the reagent section with a corresponding color gradation on the color chart. The color chart further includes a list of representative beverages relative to each color gradation and associated caffeine concentration range. Thus, a consumer is able to identify the caffeine concentration of a beverage, the names of other beverages having similar concentrations, as well as the names of alternative beverages having lower concentrations.
Therefore, a general object of this invention is to provide a caffeine testing device for detecting and displaying the caffeine concentration of a beverage.
Another object of this invention is to provide a caffeine testing device, as aforesaid, having a color-coded chart for indicating caffeine concentration ranges for comparison with the color of a test result.
Still another object of this invention is to provide a caffeine testing device, as aforesaid, which is portable and disposable.
Yet another object of this invention is to provide a caffeine testing device, as aforesaid, in which the color observed in a test area varies according to the concentration of caffeine in a tested beverage sample.
A further object of this invention is to provide a caffeine testing device, as aforesaid, which includes an impermeable polymeric layer opposite the reagent section so as to prevent a beverage sample from soaking through the reagent section.
A still further object of this invention is to provide a caffeine testing device, as aforesaid, in which the reagent section is constructed of an absorbent material.